CONTEXT AND OBJECTIVE: Pressure ulcers are lesions caused by inadequate blood flow and tissue malnourishment secondary to prolonged pressure on skin, soft connective tissues, muscle and/or bones. The authors report two distinct clinical situations of severely compromised neurological patients who shared several predisposing factors for pressure ulcers, but with opposite outcomes regarding the development of pressure ulcers.CASE REPORTS: The first case was a young patient in a persistent vegetative state who developed pressure ulcers that resulted in secondary sepsis and death. The second case was a patient with a diagnosis of amyotrophic lateral sclerosis who, in spite of being bedridden for several months with severe immobility, never developed pressure ulcers. These intriguing contrary clinical situations had already been defined by Charcot in the nineteenth century, with his creation of the expression "decubitus ominosus". He indicated that patients with amyotrophic lateral sclerosis usually did not develop this form of complication, as was illustrated by the cases presented here.